Sound reproducing system and apparatus



Feb. 23, 1937. R. D. AURANDT SOUND REPRODUCING SYSTEM AND APPARATUS 4 Filed Nov. 16, 1935 2 Sheets-Sheet 1 INVENTOR. 19 W ,Juzsu 62F200 2E Feb. 23, 1937. R. D. AURANDT SOUND REPROI DUCING SYSTEM AND APPARATUS Filed Nov. 16, 1935 2 Sheets-Sheet 2 v INVENTOR.

Patented Feb. 23, 1937 UNITED STATES PATENT OFFICE SOUND REPRODUCING SYSTEM AND APPARATUS 5 Claims.

The present invention relates to a sound reproducing system and more particularly to an improved system and apparatus for controlling the reproduction of sound from electrical transcriptions or phonograph records.

An object of the present invention is to provide a new and improved system of control for electrical sound reproducing apparatus which is adapted to be operated from a remote station.

Another object of the invention is to provide a system of control for a sound reproducing system in which the control thereof can be effected automatically by the use of push button switches.

Another object of the invention is to provide in a phonographic sound reproducing system means whereby the volume of sound reproduced thereby may be controlled from a plurality of stations.

Another object of the invention is to provide in a sound reproducing system of the character described means whereby the sound program reproduced will start at a low tonal volume and increase in response to a push button control until the desired volume is attained, and which, when stopped, will operate in a reverse manner and fade away to a zero tonal volume.

Another object of the invention is to provide a new, novel and remotely operated control device whereby the volume of sound and operation of the system may be controlled simultaneously and/or independently from a plurality of remote control stations.

The system illustrated for the purpose of describing the present invention is primarily intended for use in connection with the reproduction of organ and like music in a mortuary chapel, and since it is desirable that no blast or excessive volume be reproduced by the system except under positive control, there is provided, as a further object of the present invention, an interlocking system of switches which, under normal operation, will stop the record turning phonograph motor only when the other apparatus of the system returns to the normal program starting position and thus prea vent a subsequent starting of a program with a raised tonal volume.

Other objects and advantages of the invention will be in part pointed out hereinafter, and

in part evident to those skilled in the art as the description thereof proceeds.

In the drawings wherein there is shown, by way of illustration and not of limitation, a preferred embodiment of the invention;

Figure 1 is a diagrammatical wiring diagram showing the preferred apparatus and system of connections contemplated by this invention,

Figures 2 and 3 are perspective views of a motor operated volume controlling unit adapted for use in accordance with this invention,

Figure 4 is an end elevation of the unit illustrated in Figure 2 of the drawings, and

Figure 5 is a vertical, sectional view taken along line V-V of Figure 4 of the drawings.

As illustrated diagrammatically in Figure 1 of the drawings, the sound reproducing apparatus of the present invention comprises a sound reproducing loud speaker of the electrodynamic type, designated by the numeral ID, a phonographic reproducing unit having a record supporting platen H, an electrical pick up device l2 and a driving motor l3. Associated with the electrical pick up device l2 and the loud speaker Hi there is a thermionic tube amplifier l4 which may be of any standard type. The amplifier I4 is adapted to be energized from a 110-volt alternating current circuit, and the field coil of the loud speaker I is energized at a reduced voltage through a suitable transformer IS. The transformer l also provides a reduced potential for the other electrical devices of the system. The output of the electrical pick up device I2 is connected through wires l6 and H to the input or grid to ground terminals of the amplifier unit I, and the diaphragm actuating coil of the loud speaker III is connected to the output or speaker coil terminals of the amplifier unit I4 by means of conductors l8 and I9. From the arrangement so far described it will be seen that when the system is in operation the modulated current generated in the electrical pick up device I2 will be passed through the amplifier l4, amplified and then impressed upon the diaphragm actuating coil of the loud speaker Ill.

The thermionic tube amplifier I4 is shown as connected by means of conductors and 2| to a 110-volt circuit 22 that is connected by means of a double pole switch 23 and a wall plug 24 to any suitable power outlet. The transformer I5 is also shown as connected to the circuit 22 by means of conductors 25 and 26 and the phonograph motor IE! is shown as connected to this same circuit by means of conductors 21 and 28 through contacts 29 of a low voltage relay 30 which is adapted to be controlled, as will hereinafter appear.

The above described connections comprise what may be considered as the main power circuits of the apparatus as distinguished from the control circuits to be now described. In addition to the above apparatus, the system also includes a push button station 3| and a push button station 32, the latter of which is adapted to be located at a point remote from the other apparatus of the system. At this point it might be said that the system does not necessarily require the two above push button stations, as either one or the other might be used alone in the system. It is also conceivable that additional and similar push button stations might also be used with this system by merely connecting same in parallel with those already installed. The purpose of these push button stations 3| and 32 is to permit the control of the tonal volume of the reproduced program by means of push buttons either adjacent to or remote from the apparatus. To this end there is provided a volume control rheostat or potentiometer 33 that is connected by means of conductors 34, 35 and 36, to volume control terminals upon the amplifier l4. This rheostat 33 is adapted to be operated by an electric motor unit 3'! that is to be described in more detail hereinafter. Briefly the motor unit 37 may be described as of the alternating current type, and to provide for its rotation in two directions, it is provided with two field coils 38 and 39 which respectively cooperate with rotors 40 and 4! that are mounted upon a common shaft not shown in Figure 1 of the drawings. The shaft of the rotors 49 and 4| is connected at one end with a rotatable contact arm 42 of the rheostat 33, and at its other end it carries a rotatable contact arm 43 of a resistance potentiometer 44. This shaft also carries suitable cams that cooperate with limit switches 45 and 46, as will more fully appear in connection with the description of the remaining figures of the drawings.

From the above it will be seen that when the motor unit 3'! rotates in one direction or another it will control the position of the rotatable arm 42 of the volume control rheostat 33 and thus effect a change in the output volume of the amplifier [4. At this point it should be noted that the potentiometer 44, which is also adapted to be operated by the shaft of the motors 4i} and 4|, may beconnected to any suitable source of voltage supply. In the drawings, this supply is taken from the ground to microphone terminals of the amplifier I4. Therefore since the potentiometer contact arm 43 is movable in synchronism with the contact 42 of the volume control rheostat 33,- its position upon the potentiometer 44 will provide a voltage drop or measurement corresponding to the output volume of the amplifier l4, and therefore by connecting suitable voltmeters between the ground end of the poten tiometer 44 and the rotatable arm 43 thereof, it will be possible to obtain an indication that will be representative of the tonal output of the am plifier for the particular position of the volume control rheostat 33. As shown in the diagram, the ground side of the potentiometer 44 is connected to the amplifier [4 by means'of a conductor 41, and its high voltage end is connected by means of conductors 48 and 49 through an adjustable calibrating resistance 50 with the microphone terminal of the amplifier E4. The purpose of the adjustable resistance 53 is to provide for an adjustment of the voltage drop across the potentiometer winding 44.

Indicating meters 5| and 52, which serve to indicate upon a graduated scale the tonal output of the amplifier M, are located respectively at the push button stations 3i and 32. The meter Si is connected, by means of conductors 53 and 54,

across the ground to the moving contact portion of the potentiometer 44, and the meter 52 is connected to this same portion of the potentiometer 44 by means of conductors 55 and 56.

As previously stated, the transformer l5 serves to provide a reduced voltage for the controlled circuits and for this purpose its secondary, designated by the numeral 51, is provided with a 2d-volt and a 30-volt tap, the latter or 30-vol't tap being utilized for the circuits connected with the remote control panel and providing an increased voltage to compensate for any line drop due to the distance of the remote control panel from the other apparatus. The Zeb-volt winding of the transformer i5 is connected through conductors 58 and 59 to the field coil of the loud speaker It]. This portion of the transformer i5 is also connected by means of conductors 60 and SI with the main push button station 3!. The conductor 66 is connected to one side of a push button 82 and a push button 63 and the conductor 6| is connected through a power indicating lamp 64 and a resistance 65 and a conductor 66 to the conductor 60 to provide a return circuit.

The circuit of the lamp E4 is energized when the main control switch 23 is closed, and indicates when the main push button station is responsive to push button operation. The push button 62 is adapted when operated to produce an operation of the system which will reduce the volume of tone produced by the loud speaker It and the push button 63 is so connected that when oper ated it will cause the tonal volume of the loud speaker In to be increased. From the other contact of the push button 62 there is a conductor 61 that connects with one side of the soft motor field coil 38 and thus provides through a portion of a conductor 68, a conductor 69 and the limit switch 45, a return circuit through the conductors H! and H. As shown in the diagram, the switch 45 is open and in a position which corresponds to the normal starting condition of the circuit. The other side of the push button 63 is connected by means of a conductor 72 with one side of the loud motor field winding 39 and the circuit from this motor field winding 39 is completed through a conductor 13, the limit switch. 45 and conductors l0 and H, to the ground side of the transformer l5. seen that when the soft button has been held down until the soft motor has operated to open the limit switch 45, the rotation of the motor will cease. Under these conditions the opening of the limit switch 45 will open the circuit the low voltage relay 3E! and thus cause the contacts 28 to separate and .deenergize the motor 13 of the phonograph unit. This circuit comprises a conductor 14 which extends from the Z i-volt tap of the transformer [5 to one side of the relay 30 and conductor 14 that extends from the other side of the relay 30 to a conductor 69 that connects with the limit switch 45. The return circuit from the limit switch 45 is then esta hed through the conductors in and H to the ground side of the transformer H5. The conductor M is shown as a continuation of the conductor G8, previously referred to, which also completes a circuit through a resistance '55 an indicating lamp it that is adapted, when lighted, to indicate an energization of the relay 3S and operation of the phonograph. When the relay 3% is thus energized, its contacts 29 will be closed and as a result current will flow from the llU-Vfili; conductors 22 to the phonograph motor l3 With this circuit last described it will be through the conductors 21 and 28, the contacts 29 and a conductor I1.

The remote control panel, designated generally by the numeral I8, in addition to the indicating meter 52, is also provided with a soft push button I9, a loud push button 88 and an indicating lamp 8|. The push buttons 19 and 88 are here shown as connected at one side to the 38-volt tap of the transformer I5 by means of a conductor 82. The other side of the soft push button switch I8 is connected by means of a conductor 83 with the field coil winding 38 of the motor unit, and the other terminal of the loud push button 88 is connected by means of a conductor 84 with the loud field coil winding 39 of the motor unit. A circuit is also established for the indicating lamp 8| which comprises a conductor 85, that connects with the 30-volt tap of the transformer I5 by means of the conductor 82, through a variable resistance 86 and a conductor 81 to the conductor II, where the circuit is completed to the ground side of the transformer I5. The purpose of the variable resistance 86 is to control the voltage across the indicating lamp 8|.

The above describes in general terms the apparatus of a system operating in accordance with the preferred embodiment of the present invention. With the exception of a specially constructed motor operated volume controlling mechanism and the circuits of the system, the other apparatus, such as the transformer, meters, amplifier, phonograph and the loud speaker unit, are of standard construction and design.

Reference is now made to the remaining figures of the drawings for the purpose of describing the construction and novel features of the motor operated volume controlling mechanism which coordinates the various devices of the system. As shown in these figures of the drawings, the motor unit 31 consists of two alternating current motors designated by the numerals 88 and 89, which are mounted end to end between a pair of supporting plates 98 and 9I. The supporting plates 98 and 9I are spaced apart by means of tie rods 92 upon which the frames of the motors 88 and 89 are carried. The rotors of the motors 88 and 89 are mounted upon a single shaft 93, which is journaled in bearings 94, carried by the field frames of the motors. At one end of the shaft 93 there is a freely floating gear 95 that carries a clutch cylinder 96, and mounted upon the shaft 93, in cooperating relation with the clutch cylinder 96, there is a centrifugally operating clutch member 91. The gear 95 meshes with a gear 98 upon one end of a countershaft 99, and at the other end of the countershaft 99 there is a gear I88, which is adapted to drive a second gear I8I that is mounted upon a stub shaft I82. The gear I8I is connected with a worm I83, which drives a worm wheel I84 carried by a transversely extending shaft I85. The shaft I is rotatably carried upon arms I86 that extend outwardly from the supporting plate 98. Secured upon one end of the shaft I85 by means of a sleeve IN is a supporting shaft I88 which carries the contact arm 42 of the volume control resistor 33, and at the other end of the shaft I85 there is secured by means of a collar I89, a shaft II8 which carries the moving contact 43 of the potentiometer resistor element 44 previously referred to. The resistor elements 33 and 44 are, by virtue of the above described attachment with the shaft I85, supported thereby, and in order to prevent a rotation of the resistor unit and its inclosing housing with their respective shafts, there is provided in each instance a radially extending forked member III, each of which engage with an outwardly projecting pin II2 carried by arms II3 upon the end plate 98. At the ends of the arms I I3 there is an insulating support I I4 upon which the limit switches 45 and 48 are mounted, and in vertical alignment with the depending ends of the limit switches 45 and 46 there are provided upon the shaft I85 suitable cams H5 and III; that serve to respectively open the limit switches 45 and 46 when the shaft I85 is rotated to move the contact arms of the resistors 33 and 44 between their limits of travel.

At the other end of the motor unit, and mounted upon the plate 9|, there is a pivoted friction drag member II'I which is adapted to engage a projecting end II8 of the countershaft 99. The friction drag H1 is biased into braking engagement with the projecting end II8 of the countershaft 99 by means of a spring I I9 and prevents overrunning of the countershaft 99 when either of the limit switches 45 or 46 is opened.

With the above described arrangement it will be noted that because of the centrifugally operating clutch member 91, the rotors of the motors 88 and 89 will be permitted to start and gain speed before the load is thrown thereupon, and thus the use of a small self-starting alternating current motor unit is possible. The friction drag device I I1 will prevent any overrunning of the countershaft 99 upon a stopping of the motors irrespective of its direction of rotation. This assembly provides a complete and compact unit which, with the other described apparatus of the system, greatly simplifies the system of connections and the operation thereof, and renders possible the use of normally opened push buttons as a manual controlling means.

The operation of the system illustrated in Figure 1 of the drawings, and the apparatus illustrated in the remaining figures of the drawings, is as follows- When the apparatus and the switches of the system are in the positions as illustrated in Figure 1 of the drawings, which is the normal condition of the system when deenergized, a closing of the main switch 23 will impress the ll0-volt service voltage upon the amplifier I4 and the transformer I5. The energization of the transformer I5 in this manner will cause the power indicating lamp 64 upon the main control panel 3I, and the indicating lamp 8| upon the remote control panel 32, to light up and indicate that these panels are in operating condition. Under normal operation the stopping of a program will be effected through a depression of the soft push buttons 62 or I9, and consequently the apparatus will be left in the condition illustrated. In other words, when one or the other of the push buttons 82 or 19 is held down, the soft motor 48 will operate to its extreme soft position and the limit switch 45 will be opened and deenergize the relay 38. This is presumed to have happened.

Now to reproduce a program it is only necessary to place a record upon the phonograph platen I I and position the pickup device I2 thereupon, after which the depression of the loud push button 63 upon the panel 3|, or the loud push button 88 upon the remote control panel 32, to start the reproduction. When the push button 63 or the push button 88 is de pressed, a circuit will be established through the loud motor M which. during its initial operation, will permit the limit switch 45 to close and thus energize the indicating lamp I8 and the relay 3!). The energization of the relay 30 in this manner will cause its contacts 29 to close and thus connect the phonograph motor 13 to the l10-volt service lines. The indicating lamp will then serve to indicate that the phonograph motor has started to operate. As the push button 63 or 80, as the case may be, is retained down, the motor 4| will continue to rotate, and as a result the rotatable contact arm 42 of the volume control resistor 33 will move and increase the volume output or gain of the amplifier I4. A continued pressure upon the push button will produce constantly increasing volume of sound to be reproduced by the loud speaker it. When the volume of sound reproduced has reached the desired value, the operator will merely release the particular loud push button which he is operating. If a louder volume of sound is desired, a further pressure upon the push button 63 and/or 80 will result in such an increase, whereas if a lower volume of sound is desired, this can be accomplished by depressing either of the soft buttons 62 or 79, depending upon from which station the operation is carried out. Since the contact arm 43 of the potentiometer resistance 44 is also moved in synchronism with the contact arm 42 of the resistance 33, it will be seen that the position of the rotatable contact arm 43 upon the resistance 44 will be proportional to the total voltage drop across the resistance 44, and as a result, with the connections shown, a voltage will be impressed upon the indicating meters 55 and 52 that will serve as an index to the volume of sound being reproduced. It will be understood that the graduations of the meters 5| and 52 will not necessarily be in sound values, but may be of any arbitrary value, experience dictating at which point on the dial the particular volume desired will be found. At this point it will be noted that if the loud push buttons 53 or 88 are held down sufiiciently long, the loud motor 4! will eventually cause the limit switch 46 to be opened and thus stop further operation thereof. While an examination of the diagram of Figure 1 will show a circuit through the low voltage relay 30, which is established independently of the limit switch 45, it should be stated that the resistance of this circuit, which includes the indicating lamp 16 and the resistance 15 in series therewith, prevents the fiow of sufiicient current to operate the relay 30. The circuit referred to can be traced from the ground side of the secondary of the transformer l5, through the lower portion of the conductor H to the conductor 6|, through the power indicating lamp 64, resistance 65, resistance 15, indicating lamp l6 and then through the conductor 68 to conductor 14 through the relay 30 and back to the 24-volt tap of the transformer by way of conductor 14. The value of the resistance 15 and the resistance of the coil of the relay 30 is sufiicient at this voltage to prevent an operating current to flow through the relay coil, and therefore it is not until the limit switch 45 closes that an efiective relay operating circuit is established, as described above.

After the system has been set in operation, as above described, and a stopping thereof is desired, this can be accomplished by pressing either of the soft push buttons 62 or 19. This operation will cause the volume of sound to decrease and eventually fade away until the soft motor 40 operates to a point Where the limit switch 45 will open. The opening of the limit switch 45 will then deenergize the phonograph motor l3 and permit a removal of the record and the substitution of a new one. Then if the system is no longer required, an opening of the main switch 23 will completely disconnect the system from the power source.

While I have, for the sake of clearness and in order to disclose the invention so that the same can be readily understood, described and illustrated specific devices and arrangements, I desire to have it understood that this invention is not limited to the specific means disclosed, but may be embodied in other ways that will suggest themselves to persons skilled in the art. It is believed that this invention is new and it is desired to claim it so that all such changes as come within the scope of the appended claims are to be considered as part of this invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. In a sound reproducing system, the combination of a source of modulated current to be reproduced as sound, an amplifier for increasing the volume of said modulated current, a sound reproducer connected to said amplifier, a volume control resistance associated with said amplifier to control the tonal output thereof, a motor unit for operating said volume control resistance, a plurality of push button stations for controlling the operation of said motor unit, a limit switch operated by said motor unit when said volume control resistance has moved to its lower limit of travel in either direction, and means associated with said limit switch adapted to render said source of modulated current inoperative, whereby upon a restarting of the system the tone value of the reproduced sound will be at a low level.

2. In a sound reproducing system, the combination of a phonograph as a source of modulated current to be reproduced as sound, an amplifier for increasing the volume of said modulated current, a sound reproducer connected to said amplifier, a volume control resistance associated with said amplifier to control the tonal output thereof, a motor unit for operating said volume control resistance, a plurality of push button stations for controlling the operation of said motor unit, limit switches operated by said motor unit when said volume control resistance has moved to its limit of travel in either direction, and a relay responsive to one of said limit switches for controlling the operation of said phonograph when said volume control resistance is moved to one of its limits of travel.

3. In a sound reproducing system, the combination of a phonograph having a modulated current output, an amplifier for increasing the volume of said modulated current output, a sound reproducer connected to said amplifier, a volume control resistance associated with said amplifier, a motor unit for varying said volume control resistance, a plurality of push button stations for controlling the operation of said motor unit, limit switches for stopping said motor unit when said volume control resistance has been operated to either of its extreme positions, and a relay responsive to one of said limit switches for controlling the operation of said phonograph when said volume control resistance is moved to its low tone position.

4. In a remote control system of the character described, the combination of an amplifier having a volume Control resistor associated therewith, a uni-directional electric motor adapted to operate said volume control resistor in one direction, a second uni-directional motor adapted to operate said volume control resistor in a reverse direction, limit switches controlled by said motors adapted to stop same when said resistor is operated to either of its extreme positions, the rotors of said motor units being mounted upon the same shaft, and a two-way centrifugally operating clutch means in the driving connection between said motors and said volume control resistor.

5. A motor unit for operating a volume con- 15 trolling resistor in a system of the character above described, comprising a support, two alternating current field coils mounted end to end upon said support, a shaft journaled upon said support having a rotor associated with each of said field coils, a countershaft mounted adjacent and parallel to said first shaft, a gear upon said second shaft meshing with a freely rotatable gear upon said first shaft, a centrifugally operating clutch connecting said first shaft and said latter gear adapted to permit a starting of either of said motors under a no-load condition, and a friction drag upon said second shaft adapted to prevent an overrunning thereof after said clutch is disengaged.

RICHARD D. AURAND'I. 

